Hallux valgus is a deformity of the foot characterized by lateral deviation of the great toe with medial deviation of the first metatarsal bone. This often leads to irritation of the bursal sac on the medial side of the metatarsophalangeal joint with thickening and pain (the bunion).
The condition may develop in childhood, but often does not start to cause symptoms until middle age. It is probably hereditary, but often aggravated by inappropriate shoewear.
When the deformity is severe and causes symptoms, the treatment is often surgery to correct the hallux valgus and excision of the bunion.
Splints and braces have been used for conservative treatment to prevent the deformity from getting worse, as well as for postoperative wear to prevent recurrence. Splints and braces fall into the following categories:
1) Rigid splints which may be custom-molded or ready made. Custom-molded rigid splints are usually made of a thermoplastic that is molded to the medial aspect of the foot and great toe. The foot and great toe are then strapped to the splint by means of hook and loop fasteners. Examples are Donatto et al (Orthopedics Vol. 15, No. 4, 1992) and Lieberson et al (Orthopedics, Vol. 14, No. 5, 1991), and Cook (U.S. Pat. No. 4,729,369 in 1988). Ready-made braces are usually an unmolded straight splint made of plastic or metal against which the foot and great toe are attached. Examples are Shaffer (U.S. Pat. No. 4,856,505 in 1988), and Darco (Berkemann catalog--page 6). PA0 2) Flexible braces are made of fabric material that circumferentially covers the forefoot and great toe. Correction is obtained by use of a strap that is attached to the brace by means of hook and loop fasteners that pulls the great toe into the corrected position. Nakamura (U.S. Pat. No. 4,644,940 in 1987) has a strap that crisscrosses the foot to obtain the varus pull on the great toe. Both Fabricant (U.S. Pat. No. 4,632,103 in 1986) and Berkemann's bunion day-splint describe a strap that extends from the great toe along the medial aspect of the foot and around the heel, ending on the anterolateral aspect of the foot onto which it is attached. Jacoby (U.S. Pat. No. 4,940,046 in 1990) has a strap that extends from the lateral aspect of the great toe across the top of the metatarsophalangeal joint of the great toe to the medial aspect of the foot. PA0 1. The rigid braces including the Berkemann toe straightening device (U.S. Pat. No. 2,958,324 in 1960, and Berkemann catalog--page 4), made of thermoplastic or metal are bulky and uncomfortable to wear. They are usually worn only at night since it is difficult to walk in them. PA0 2. The flexible braces can be worn in shoes. However the use of straps with hook and loop fasteners placed over the fabric of the brace add considerably to the bulk of the contraption, and are very difficult to fit in regular shoes. Extra width or depth shoes are usually needed. The Nakamura and Jacoby braces use straps with hook and loop fasteners. With constant walking in the brace, the hook and loop fastener loosens, and correction is lost. Constant readjustment through the day is needed to keep the strap taut to maintain correction. The Berkemann bunion day-splint consists of a midfoot binder that compresses the midfoot, and a separate toe sock that is attached by a strap that is pulled around the back of the heel. The toe sock is placed on the great toe, and the strap pulls the great toe into the corrected position. The strap may be an elastic or inelastic band, but the principle is the same. The correction is obtained by pulling the great toe and holding it in position, by winding the strap around the back of the heel. This causes pressure on the heel and skin irritation around the heel. PA0 1) Ease of applying and removing PA0 2) Correction of the hallux valgus without adding so much bulk, so that it is comfortable even in a regular shoe PA0 3) Consistent corrective force on the hallux valgus that is not lost as the brace is worn through the day, and that does not require repeated adjustment to obtain continued correction PA0 4) Does not put pressure on the heel and cause heel irritation.
Another example of a rigid splint is Berkemann (U.S. Pat. No. 2,958,324 in 1960) which consists of a rigid toe splint connected to a fulcrum on the foot, the other arm connected proximally to an elastic band. The elastic band through the fulcrum will bias the great toe into a varus position. A refinement is now manufactured by Berkemann Co. (Catalog--page 4), but the principle remains the same.
The braces that are available on the market at this time have the following disadvantages:
Hence there is still a great need for a device that accomplishes all of the following: